US2441557A - Selective signaling system - Google Patents
Selective signaling system Download PDFInfo
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- US2441557A US2441557A US576835A US57683545A US2441557A US 2441557 A US2441557 A US 2441557A US 576835 A US576835 A US 576835A US 57683545 A US57683545 A US 57683545A US 2441557 A US2441557 A US 2441557A
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- G—PHYSICS
- G07—CHECKING-DEVICES
- G07C—TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
- G07C1/00—Registering, indicating or recording the time of events or elapsed time, e.g. time-recorders for work people
- G07C1/20—Checking timed patrols, e.g. of watchman
Definitions
- This invention relatesto signaling systems and particularly to a selective signaling system in which a common control circuit is operable in a plurality of difierent manners from a plurality of remote points to identify the points from which i signals are transmitted.
- the object of the invention is to simplify the transmission of station-identifying signals over a single pair of conductors to a central point, and to otherwise provide an improved system of signaling which is particularly applicable to multiparty line telephone systems and to a watchmans reporting system.
- each of a multiplicity of stations having access to a common two-conductor signaling channel is distinctively characterized at the station by means which functions to determine the character of the signaling current, derived from a source of alternating current, which is transmitted to a common point incident to the connection of the alternating current source to the channel at the particular station.
- one or both conductors of the two-conductor signaling channel is, or are connected to corresponding connecting terminals at each station either directly or by way of similarly and/or oppositely poled dry rectifiers so as to distinctively identify the signaling channel at each station and to thereby determine the character of the signaling current transmitted over either or both conductors of the channel incident to the connection of the alternating current source to the channel appearances at the stations.v
- Another feature of the invention resides in a common signal receiving circuit, located at a central point, which responds selectively to the si nals transmitted from each station in a manner corresponding to the particular characterization of the channel appearance at the station from which the signals are transmitted, and to selectively control the operation of a signal device which identifies the station from which the signals are transmitted.
- a further feature of the invention resides in the use'of means for successively operating each station-identifying signal device at a central point and maintaining each signal device operated until automatically erased by the subsequent transmission of a signal from another station.
- This feature finds particular application to a watchmans reporting system in that the progress of the watchman over his post may be clearly supervised and'his whereabouts at any particular time may be readily determined.
- a. signal receiving circuit may be located at each of a plurality of locations and selectively operated from corresponding signaling stations to control the operation of a. signal device corresponding to the signaling station.
- Fig. 1 illustrates a common signaling channel terminating at each of fifteen different stations in .a differently polarized line appearance; a common signal receiving circuit terminating the channel at a, central location; a plurality of selectively operable station identifying signals; and supervisory signaling equipment;
- Fig. 2 illustrates a modification of the signal control circuit at the central location
- Fig. 3 illustrates a variation of the signal receiving circuit of Fig. 1 in which a separate signal receiving circuit is employed to indivdually control the station identifying signals.
- the designation SC identifies a, two-wire signaling channel extending from a central point or station S and terminating at'each of fifteen stations in a jack, such as jacks, l0, l'l, I2, I3, l4, l5, l6, l1, l8, I9, 20, 2
- a jack such as jacks, l0, l'l, I2, I3, l4, l5, l6, l1, l8, I9, 20, 2
- the jacks In to 24, inclusive in the embodiment shown in Fig. 1, represent fifteen stations which a watchman, for example, must visit while making his rounds in a protected area and from which he must report or "signal in to the supervisory station S.
- Each jack is equipped with the usual tip, ring, and sleeve terminals, the last of all of which are connected to ground potential at 25 by way of conductor 26.
- the ring terminal of jack I0 is open-circuited while the tip terminal is connected to the conductor 28 of thesignaling channel SC by way of a positively poled dry rectifier 29.
- the terminals of jack II are connected in the same manner as are the terminals of jack I0 except that the negatively poled dry rectifier 30 is substituted for the positively poled rectifier 29.
- the ring terminal of jack I2 is open-circuited and the tip terminal thereof is connected directly to the conductor 28 of the signaling channel SC.
- the tip terminal of jack I3 is open-circuited and the ring terminal thereof is connected to the conductor 21 of the signaling channel by way of the negatively poled rectifier 3
- the tip terminal of jack I4 is connected to conrectly to conductor 23 of the signaling channel SC While the ring terminal is connected to. con- 7 ductor 2? by way of the negatively poled 'rectifier El.
- the ring terminal is connectedltolconductor 2i of signaling channel SC by way of the positively poled rectifier 38.
- the tip and ring terminals of jack I8 are connected to conductors 28 and 27, respectively,lof the signaling channel by way of the positively poled rectifiers 39 and 4183, respectively.
- the tip and ring terminals of jack [9 are connected to conductors 23 and 2?, respectively, of the signaling channel by Way of the negatively poled rectifier ll and the positively poled rectifier 32, respectively.
- the tip terminal of jack 2!] is connected directly to conductor 28 of the signaling channel while the ring terminal is connected to conductor El by way of the positively poled rectifier 3-3.
- the tip terminalof jack 2! is open-circuited while the ring terminal is connected directly to the conductor 21 of the signaling channel SC.
- the tip terminal of jack 22 is connected to the conductor 28 of the signaling channel SC by way of the positively poled rectifier 44 while the ring terminal thereof is connected directly to conductor 27!.
- The, terminal connections of jack 23 to the signaling channel SC are-the sameas those-of jack 22 except that the negatively poled rectiof the stations ID to 24, inclusive.
- Each relay controls a plurality of armatures and contacts which are interconnected in such manners that when the relays are operated in fifteen diiierent combinations, fifteen different operating circuits are completed to the signal lamps shown in the upper right portion of Fig. 1. 1
- the Watchman may be provided with a portable hand generator or magneto 69 which is plug-ended as indicated by the plug 6
- one terminal of the-output coil of the generator 63 is connected yto the tip and ring contacts of the plug 6
- the generator output is impressed across the tip-and sleeve, and ring and sleeve terminals of the plug 6
- Both tip and ring terminals of jack 2,4 are connected directly to the conductors 28 and 21,, respectively, of the signaling channelSC'.
- the signaling channel terminates in two sets of signal receiving relays 46, 4.1 and 48, 419
- Each re lay winding is shunted by a dry rectifier and is serially connected to another rectifier, the two rectifiers being oppositely poled.
- Relayv 45 is shunted by the negatively poled rectifier 50,, While the positively poled rectifier 5.1 is connected in series with its winding; relay 4! is shunted by the positively poled rectifier 52, While the negatively poled rectifier '53. is connectedin series with its Winding.
- relays G8 and it bear the same circuit relations to relays G8 and it as do the rectifiers 5B,"5I, 52 and 53', respectively, to the relays 46 and-4 1, as just described.
- the relays 4,6 and 41. are connected to the conductor 2'! of the. signaling. channel SC and therefore respond selectively, to signals transmitted over conductor 21 from any of. the stations H! to 24, inclusive, While relays 4B and 49 are connected to conductor 28 of .”signaling' channel SC andtherefore respondselectively to signals transmitted over. conductor. 28 fromlany 6
- relay 18 After an interval of time required toheat the thermistor 69, relay 18 operates on the negative half cycles traversing its lower winding and locks to ground at the back contact of key 14 by way of its upper winding and the shunting rectifier 12. At its lower armature and front contact, relay 18 completes an obvious operating circuit for lamp signal 15. Thus, when the watchman signals in from-the last station 24,
- a lamp signal corresponding to any station may be maintained operated until the watchman signals in from the next station. This may be accomplished in the manner illustrated in Fig. 2. Instead of the lamp signals l8a, Ila, etc., being controlled directly from the signal receiving relays 4'6, 4'1, 48, and 49, they are indirectly controlled by these relays through an individual, double wound, locking relay such as re-. lays 88, 8
- and 82 comprise a series chain including the armatures and back contacts of all succeeding relays in the chain.
- relay 88 when relay 88 operates to light lamp signal 18a, it will lock to maintain the lamp lighted until relay 8
- will-be held operated to maintain lamp
- Fig. 3 there are illustrated three stations indicated by the signal lamps 85, 86 and 81. These lamps may constitute call signals for stations on a multiparty telephone line or of an intercommunicating system.
- This figure also depicts a variation of the system shown in Fig. l, where it may be found desirable to control each lamp signal by means of its own individual signal receiving circuit.
- the relays and rectifiers of this figure bear the same identification numerals asthe corresponding relays and rectifiers of Fig. 1 and it-is to be understood that they function in the same manner. It will be observed that, the uppermost group of relays requires the transmission of the positive half cycles over cohrductor. 28 to operate relay 49 and thus complete an operating circuit for the lamp signal 85.
- the lamp signal 85 would be operated by a signal transmitted from station IU of Fig. 1.
- lamp signal 86 would operate to indicate the transmission of a signal from station ll, of Fig. 1, and
- lamp signal 81 wouldbe operated in response to a signal transmitted from station l2.
- each calling station would be equipped with a keyior each called station which would function to polarize the line in the manner in which it is permanently polarized by the rectifier-jack combinations shown in Fig. 1.
- an outlet for said line ateach station each consisting of a groundedterminal and one or more line terminals whereby one of the conductors of said line terminates at certain of said outlets and both of the conductors of said line terminate at certain other of said outlets, means connecting one or both conductors of said line directly to their corresponding terminals at certain of said outletsjmeans comprising similarly poled unidirectional current/conducting devices connecting one or both conductors of said line to their corresponding. terminals at certain other of said outlets, means comprising'difierently poled. unidirectional current conduoting devices connecting the conductors of said line to their corresponding terminals atstill certain other of said
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- General Physics & Mathematics (AREA)
- Sub-Exchange Stations And Push- Button Telephones (AREA)
Description
y 1943- L.'J. BOWNE 2,441,557
SELECTIVE SIGNALING SYSTEM Filed Feb. 8, 1945 2 Sheets-Sheet 1 lNl/EN TOR L.J. BOWNE ATTORNEY Ma Is, 1948.
L. J. BOWNE SELECTIVE S IGNALING SYSTEM Filed Feb. 8, 1945 2 Sheets-Sheet 2 lNl/ENTOR L. J. BOWNE ATTORNEY Patented May 18, 1948 SELECTIVE SIGNALING SYSTEM Langford J. Bowne, Howard Beach, N. Y., as-
signor to Bell Telephone rated, New York, N. Y.,
York
Laboratories, Incorpoa corporation of New Application February 8, 1945, Serial No. 576,835
Claims. (Cl. 1'l7353) This invention relatesto signaling systems and particularly to a selective signaling system in which a common control circuit is operable in a plurality of difierent manners from a plurality of remote points to identify the points from which i signals are transmitted.
The object of the invention is to simplify the transmission of station-identifying signals over a single pair of conductors to a central point, and to otherwise provide an improved system of signaling which is particularly applicable to multiparty line telephone systems and to a watchmans reporting system.
In accordance with one feature of the invention each of a multiplicity of stations having access to a common two-conductor signaling channel is distinctively characterized at the station by means which functions to determine the character of the signaling current, derived from a source of alternating current, which is transmitted to a common point incident to the connection of the alternating current source to the channel at the particular station. More particularly, one or both conductors of the two-conductor signaling channel is, or are connected to corresponding connecting terminals at each station either directly or by way of similarly and/or oppositely poled dry rectifiers so as to distinctively identify the signaling channel at each station and to thereby determine the character of the signaling current transmitted over either or both conductors of the channel incident to the connection of the alternating current source to the channel appearances at the stations.v
Another feature of the inventionresides in a common signal receiving circuit, located at a central point, which responds selectively to the si nals transmitted from each station in a manner corresponding to the particular characterization of the channel appearance at the station from which the signals are transmitted, and to selectively control the operation of a signal device which identifies the station from which the signals are transmitted.
A further feature of the invention resides in the use'of means for successively operating each station-identifying signal device at a central point and maintaining each signal device operated until automatically erased by the subsequent transmission of a signal from another station. This feature finds particular application to a watchmans reporting system in that the progress of the watchman over his post may be clearly supervised and'his whereabouts at any particular time may be readily determined.
In accordance with a modification of the signaling system of this invention a. signal receiving circuit may be located at each of a plurality of locations and selectively operated from corresponding signaling stations to control the operation of a. signal device corresponding to the signaling station.
These and other features of the invention will be readily understood from the following detailed description when read in connection with the accompanying drawings, in which:
Fig. 1 illustrates a common signaling channel terminating at each of fifteen different stations in .a differently polarized line appearance; a common signal receiving circuit terminating the channel at a, central location; a plurality of selectively operable station identifying signals; and supervisory signaling equipment;
Fig. 2 illustrates a modification of the signal control circuit at the central location; and.
Fig. 3 illustrates a variation of the signal receiving circuit of Fig. 1 in which a separate signal receiving circuit is employed to indivdually control the station identifying signals.
Referring now to Fig. 1, the designation SC identifies a, two-wire signaling channel extending from a central point or station S and terminating at'each of fifteen stations in a jack, such as jacks, l0, l'l, I2, I3, l4, l5, l6, l1, l8, I9, 20, 2|, 22, 23 and 24. It is intended that the jacks In to 24, inclusive, in the embodiment shown in Fig. 1, represent fifteen stations which a watchman, for example, must visit while making his rounds in a protected area and from which he must report or "signal in to the supervisory station S. Each jack is equipped with the usual tip, ring, and sleeve terminals, the last of all of which are connected to ground potential at 25 by way of conductor 26.
The ring terminal of jack I0 is open-circuited while the tip terminal is connected to the conductor 28 of thesignaling channel SC by way of a positively poled dry rectifier 29.
The terminals of jack II are connected in the same manner as are the terminals of jack I0 except that the negatively poled dry rectifier 30 is substituted for the positively poled rectifier 29.
The ring terminal of jack I2 is open-circuited and the tip terminal thereof is connected directly to the conductor 28 of the signaling channel SC.
The tip terminal of jack I3 is open-circuited and the ring terminal thereof is connected to the conductor 21 of the signaling channel by way of the negatively poled rectifier 3|.
' The tip terminal of jack I4 is connected to conrectly to conductor 23 of the signaling channel SC While the ring terminal is connected to. con- 7 ductor 2? by way of the negatively poled 'rectifier El.
The tip terminal of jack His open-circuited'.
and the ring terminal is connectedltolconductor 2i of signaling channel SC by way of the positively poled rectifier 38.
The tip and ring terminals of jack I8 are connected to conductors 28 and 27, respectively,lof the signaling channel by way of the positively poled rectifiers 39 and 4183, respectively.
The tip and ring terminals of jack [9 are connected to conductors 23 and 2?, respectively, of the signaling channel by Way of the negatively poled rectifier ll and the positively poled rectifier 32, respectively.
The tip terminal of jack 2!] is connected directly to conductor 28 of the signaling channel while the ring terminal is connected to conductor El by way of the positively poled rectifier 3-3.
The tip terminalof jack 2! is open-circuited while the ring terminal is connected directly to the conductor 21 of the signaling channel SC.
The tip terminal of jack 22 is connected to the conductor 28 of the signaling channel SC by way of the positively poled rectifier 44 while the ring terminal thereof is connected directly to conductor 27!. V p
The, terminal connections of jack 23 to the signaling channel SC are-the sameas those-of jack 22 except that the negatively poled rectiof the stations ID to 24, inclusive. Each relay controls a plurality of armatures and contacts which are interconnected in such manners that when the relays are operated in fifteen diiierent combinations, fifteen different operating circuits are completed to the signal lamps shown in the upper right portion of Fig. 1. 1
' As a means for transmitting the'signals, the Watchman may be provided with a portable hand generator or magneto 69 which is plug-ended as indicated by the plug 6|. one terminal of the-output coil of the generator 63 is connected yto the tip and ring contacts of the plug 6| which are shown strapped together while the other output 'coilterminal is connected to the sleeve contact of the'plug 61. Thus, when the hand crank 62 is actuated in the Well-known manner, the generator output is impressed across the tip-and sleeve, and ring and sleeve terminals of the plug 6|.
It will .now be assumed that the Watchman in starting his rounds visits the station "indicated bythe jack Ill. "Hefiinserts the lpl'ug'fii of; his portable generatori'intothei'ja'ck ill and operates the crank" 62; remained, thef ring terminal of jack [0 is open-circuit'ed s'o thatin signaling from station rle'omycsnsuetorna of r the signaling channel SgC'is utilized. With plug fier 35 is substituted for the positively poled V rectifier i l.
Both tip and ring terminals of jack 2,4 are connected directly to the conductors 28 and 21,, respectively, of the signaling channelSC'.
From the foregoing description of the various jack terminal connections it is apparent that the line appearance of the tWOr-COIIdJlCtOI line SC is characterized differently. at each of the fifteen stations indicated.
At the central or supervisory station S, the signaling channel terminates in two sets of signal receiving relays 46, 4.1 and 48, 419 Each re lay winding is shunted by a dry rectifier and is serially connected to another rectifier, the two rectifiers being oppositely poled. Relayv 45, is shunted by the negatively poled rectifier 50,, While the positively poled rectifier 5.1 is connected in series with its winding; relay 4! is shunted by the positively poled rectifier 52, While the negatively poled rectifier '53. is connectedin series with its Winding. The rectifiers '54,, 55, 56 and 5? bear the same circuit relations to relays G8 and it as do the rectifiers 5B,"5I, 52 and 53', respectively, to the relays 46 and-4 1, as just described. The relays 4,6 and 41. are connected to the conductor 2'! of the. signaling. channel SC and therefore respond selectively, to signals transmitted over conductor 21 from any of. the stations H! to 24, inclusive, While relays 4B and 49 are connected to conductor 28 of ."signaling' channel SC andtherefore respondselectively to signals transmitted over. conductor. 28 fromlany 6| inserted in jack' flj'the following circuit is completedil from ground; 'at'li2'5, sleeve. terminals of; jack lil and pl-ugfifl ,Thut'put coil; of generator 612, tip terminals offplugiiilj and'jack if, rectifier 2Q, conductor 28, winding of relay 49;,rectifiers 5.? and 54 to ground; the positive half cycles traverse circuit; 'Relay 49 operates in this circuit and at its. outermost armature and front contact'coinplet'esI'an energizing circuit for lamp signal 'llla' which may be traced frorngrourid at '64,'through the secondary winding of transformer 65.; whose primary winding is connectedlajcro'ssthe,alternating current source at, conductor. 61 filament of lamp. 1.0a, back contact andfiith armature of relayifi, back-contact andthird arHiatur'e of relay 4],: back contact and third arma'tur'e of relay, 48,, \front contact and fifth'larmature (if relay lQ, to ground. 'I he lamp" [0a is: lighted. in this circuit ts indicate to a supervisorilocated at station S, that the Watchman haslrepor'ted' inat'station "it. As will be described hereinafter, 'theflig'htejd lamp signal may be locked operated'if condition warrant.
As the watchman progresses through the area assigned to him, he 'visits' the remaining stations H told, inclusive, insertsfthe lfilug lil. of the generator 60. in the jack 'at eachfstation, and Vactuates the generator crank It is deemed unnecessary to, describei'ri detailthe signaling circuits developedas aresult or thes'ignaling operation at Ieach station whichfresmtsLin the o erat on a re reedi m S a at tions. These circuits, however, will now be r fl n ic e f Y et ia on H t e e at ve a t e ele ra r the conductor 28, rectifiers En and-55 and the Winding. of'relay 4?. Rela iliop'erates and its fourth armature cooperates with thefi fth armatureof relay '49, thejfourthjarmature; oi -relay; 41 nd,.the seventh atu e of; elay n c m.- pletin an ope t n l r ui or-lamp 1 1 4 Erom station 1 lbq hfhalf. cycles. tav r Qnductor 28 causing both: relays *4 8,;and;.4S-; tooperateandec'omplete;anioperating. circuit, fonlamp signal f I'Za. From station 1 l 3.- negative half cycles traverse; conductor ZTitQQfiMSQT-EIBJY 411F Operate and complete anloperating circuit. for 1amp:sig.-
cycles traverse conductor 21 causing relays 49 and 41 to operate and complete an operating circuit for lamp signal l4'a. The polarity at station I 15 on the tip conductor is the reverse of that at station I4 so that relays 48' and 41 operate and complete an operating circuit for lamp signal 1 5a. From station l6 both half waves traverse conductor '28 and the negative half waves traverse,-
I the ringer 13 and lamp 15 are operated to furnish both audible and visual signals indicating the signaling in operation from station 24. These signals will persist until the attendant at the station S actuates key 14 to open the locking cir- 'cuit for relay 18. v
If desirable, a lamp signal corresponding to any station may be maintained operated until the watchman signals in from the next station. This may be accomplished in the manner illustrated in Fig. 2. Instead of the lamp signals l8a, Ila, etc., being controlled directly from the signal receiving relays 4'6, 4'1, 48, and 49, they are indirectly controlled by these relays through an individual, double wound, locking relay such as re-. lays 88, 8| and 82. Such relays operate by way of their left-hand windings, and lock by way of is noted that the locking circuits for relays 88,
8| and 82, comprise a series chain including the armatures and back contacts of all succeeding relays in the chain. Thus, when relay 88 operates to light lamp signal 18a, it will lock to maintain the lamp lighted until relay 8| is operated. The locking circuit for relay 88 is then opened and lam-p 18a is extinguished. Similarly, relay 8| will-be held operated to maintain lamp |a lighted until someother relay such as relay 82, for example, is operated. In this manner the lighted signal'lamp serves to indicate the last station from which the watchman has reported and the'attendant is thus continuously apprised of the whereabouts of the watchman.
In Fig. 3 there are illustrated three stations indicated by the signal lamps 85, 86 and 81. These lamps may constitute call signals for stations on a multiparty telephone line or of an intercommunicating system. This figure also depicts a variation of the system shown in Fig. l, where it may be found desirable to control each lamp signal by means of its own individual signal receiving circuit. The relays and rectifiers of this figure bear the same identification numerals asthe corresponding relays and rectifiers of Fig. 1 and it-is to be understood that they function in the same manner. It will be observed that, the uppermost group of relays requires the transmission of the positive half cycles over cohrductor. 28 to operate relay 49 and thus complete an operating circuit for the lamp signal 85. Thus, the lamp signal 85 would be operated by a signal transmitted from station IU of Fig. 1. Similarly, lamp signal 86 would operate to indicate the transmission of a signal from station ll, of Fig. 1, and ,lamp signal 81 wouldbe operated in response to a signal transmitted from station l2. Inthe use of this arrangement in a multiparty line telephone system, each calling station would be equipped with a keyior each called station which would function to polarize the line in the manner in which it is permanently polarized by the rectifier-jack combinations shown in Fig. 1.
What is claimed is:
1. The combination in a signaling system of a two-conductorline, signal transmitting stations,
an outlet for said line ateach station, each consisting of a groundedterminal and one or more line terminals whereby one of the conductors of said line terminates at certain of said outlets and both of the conductors of said line terminate at certain other of said outlets, means connecting one or both conductors of said line directly to their corresponding terminals at certain of said outletsjmeans comprising similarly poled unidirectional current/conducting devices connecting one or both conductors of said line to their corresponding. terminals at certain other of said outlets, means comprising'difierently poled. unidirectional current conduoting devices connecting the conductors of said line to their corresponding terminals atstill certain other of said
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US576835A US2441557A (en) | 1945-02-08 | 1945-02-08 | Selective signaling system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US576835A US2441557A (en) | 1945-02-08 | 1945-02-08 | Selective signaling system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2441557A true US2441557A (en) | 1948-05-18 |
Family
ID=24306205
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US576835A Expired - Lifetime US2441557A (en) | 1945-02-08 | 1945-02-08 | Selective signaling system |
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| Country | Link |
|---|---|
| US (1) | US2441557A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2541461A (en) * | 1948-04-13 | 1951-02-13 | Churchill Albert | Electronic combination switch |
| US2637017A (en) * | 1953-04-28 | Translating circuit | ||
| US2639415A (en) * | 1948-10-27 | 1953-05-19 | Bell Telephone Labor Inc | Indicator selecting and lock-in circuit |
| US2686907A (en) * | 1950-11-21 | 1954-08-17 | Otis Elevator Co | Elevator car position indicator apparatus |
| US2736017A (en) * | 1956-02-21 | Display indicator and control system | ||
| US3140468A (en) * | 1960-05-04 | 1964-07-07 | Gen Signal Corp | Selective calling system |
| US3245070A (en) * | 1962-02-14 | 1966-04-05 | Call Boy Systems Inc | Call system for hostelries |
| US3475747A (en) * | 1964-03-07 | 1969-10-28 | Shunsei Kratomi | And-circuit-controlled program switch having matrix of cord connectors |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1540786A (en) * | 1923-01-11 | 1925-06-09 | Automatic Electric Co | Telephone system |
| GB314112A (en) * | 1928-03-22 | 1929-06-24 | Siemens Brothers & Co Ltd | Improvements relating to electrical signalling systems |
| GB363696A (en) * | 1929-06-21 | 1931-12-21 | Ericsson Telefon Ab L M | Improvements in electrical signalling and operating circuits |
| DE647724C (en) * | 1937-07-10 | Siemens & Halske Akt Ges | Signaling device with on and reset from the transmitter | |
| US2298840A (en) * | 1938-03-04 | 1942-10-13 | American District Telegraph Co | Alarm system |
-
1945
- 1945-02-08 US US576835A patent/US2441557A/en not_active Expired - Lifetime
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE647724C (en) * | 1937-07-10 | Siemens & Halske Akt Ges | Signaling device with on and reset from the transmitter | |
| US1540786A (en) * | 1923-01-11 | 1925-06-09 | Automatic Electric Co | Telephone system |
| GB314112A (en) * | 1928-03-22 | 1929-06-24 | Siemens Brothers & Co Ltd | Improvements relating to electrical signalling systems |
| GB363696A (en) * | 1929-06-21 | 1931-12-21 | Ericsson Telefon Ab L M | Improvements in electrical signalling and operating circuits |
| US2298840A (en) * | 1938-03-04 | 1942-10-13 | American District Telegraph Co | Alarm system |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2637017A (en) * | 1953-04-28 | Translating circuit | ||
| US2736017A (en) * | 1956-02-21 | Display indicator and control system | ||
| US2541461A (en) * | 1948-04-13 | 1951-02-13 | Churchill Albert | Electronic combination switch |
| US2639415A (en) * | 1948-10-27 | 1953-05-19 | Bell Telephone Labor Inc | Indicator selecting and lock-in circuit |
| US2686907A (en) * | 1950-11-21 | 1954-08-17 | Otis Elevator Co | Elevator car position indicator apparatus |
| US3140468A (en) * | 1960-05-04 | 1964-07-07 | Gen Signal Corp | Selective calling system |
| US3245070A (en) * | 1962-02-14 | 1966-04-05 | Call Boy Systems Inc | Call system for hostelries |
| US3475747A (en) * | 1964-03-07 | 1969-10-28 | Shunsei Kratomi | And-circuit-controlled program switch having matrix of cord connectors |
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